Neurophysiology and neuroanatomy of
the mammalian central visual pathways

Our laboratory aims to understand
the physiological properties and anatomical connections of neurons
in visual areas of mammalian cerebral cortex. The ultimate goal
of this work is to understand visual perception in terms of its
underlying neural substrates. We now know that there are over
2 dozen distinct areas of mammalian cerebral cortex with visual
functions, yet we do not know why there are so many visual areas,
or indeed how single neurons in any area come to have the functional
properties that they do. It is also now clear that the responses
of neurons are not so rigidly hardwired as previously thought.
Rather, a single visual neuron's responses to a given stimulus
vary dynamically according to the context in which that stimulus
is viewed. Specifically, although responses can be evoked from
a neuron only when stimuli fall within a restricted portion of
the visual field, stimuli falling outside that region do not themselves
evoke responses but at any moment can dramatically enhance or
suppress a simultaneously evoked response. A major focus of our
research is understanding this phenomenon and its development,
crucial to our basic understanding of how the brain dynamically
transforms sensory signals into neural responses. A second focus
of our work is characterizing the visual response properties of
neurons in a number of different areas of cerebral cortex; understanding
differences among areas will clarify the perceptual abilities
mediated by those areas. To address these questions, we employ
both electrophysiological recording as well as neuroanatomical
techniques; these allow one to study not only the physiological
properties of brain cells, but also the underlying structural
basis for how such functional properties are constructed by the
brain.

Xiao J, Levitt JB, Buffenstein R. 2006. The use of a novel and simple method of revealing neural fibers to show the regression of the lateral geniculate nucleus in the naked mole-rat (Heterocephalus glaber). Brain Res. 1077: 81-89.